Gear-grinding machine.



F. A. 'WAR-D au W41.. NL TAYLOR.

amvunmnm MACHINE.

APPLICATION FILED 00T. 15, 1909.4

Pai-,snm muyl 21, 191- @WPG Patented Jly 21,1914.

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T. A. WARD L W. N. TAYLOR. GEAR GRINDING MACHINE. AJPVPLIOATION FILED 001215) 1909. 5104589 PQ Ai WARD & w. N. TAYLOR.

' GEAR GBINDING MACHINE. 4 PBmoATIoN FILED coma, 1909.l l 1,104,589 j 1^ Paenma'July 21, .1914.

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F. A. WARD & W. N. TAYLOR. GEAR GRINDING MACHINE. yAI'ILHJAJIION FILED 00T.1`5, 1909.

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Patented July 21.19.14,

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FEREDERICK ALEXANDB. WARD AND WILLIAM NEWTON TAYLOR., 0F TOLEDO, OHIO.

GERfGRINDING MACHINE.

To all whom it may concern:

Be it known that we, FREDERICK A. WARD and WILLIAM N. TAYLOR, citizens of the United States, and residents'of Toledo, in the county of Lucas and State of Ohio, have invented certain new anduseful Tmprovements in Gear-Grinding Machines-v; and we ticularly to gear trimming orgrinding ma,

chines, including means for trimming or truing the grinding medium thereof after operating on the tooth of a gear, together with means for supporting and indexing the gear to be ground, and means for imparting proper relative movements to the grinding trimming or truing mechanism and the gear supporting means.4

Considerable difficulty" has been experienced in the manufacture of gears due to the warping occurs during the hardening or tempering process. This warping, while it may be very slight, is very perceptible in a running thereof, causing what may be termed a noisy or rattling gear, which is most objectionable when present in ther gearing of automobiles or other machines in which quietness and smoothness ofrunning is desired. Attempts have been made to true the gear teeth after the tempering thereof by passing a grinding-medium across the same, but these so have all been impracfar as we are aware due to the absence of tical and unsuccessful means for trimming the grinding-medium to compensate for the wear loccasioned by each grinding operationj The object of our invention is to obviate the above difficulties and to make the mechanical truin of gears possible'by the provision, in com ination with a grinding-medium movable relative to the teeth of agear which is mounted for a properly timed intermittent rotation, of highly efficient mechanism for automatically coacting surface of the grinding-medium to cause it to conform to the shape and size of Specification of Letters Patent. Application med October 15, 1909. Serial No. 522,802. y

vted lines :u m and m 1n Fig. 1,

thereof, whichv invariably fait dotted une t t in rige..

trimming the gearv Patented Jury ai, i914.

the teeth acted on, so'that when the trimming or truing of thev gear 1s completed the contour of each tooth conforms exactly to that of all the others.

A further object of our invention is the provision of simple and efiicient means for imparting a predetermined movement to the grinding-medium relative to its plane of reciprocatory movement whereby to compensate for the wear or gradually diminishing size of the grinding-'medium after each operation on the gear. y

The operation, ment of the parts of the-invention are fully described in the following specification, and illustrated in the accompanying drawings, in which, Y

Figure'l is a side elevationof a machine embodying the features of our invention. Figs. 2 and 3 are partial transverse sections ofthe same taken, respectively, on the dotthe former showing the rear trimmers elevated as they appear immediately after making a c ut, and the latter showing both sets of trimmers in lowered or normal position. Fig. 4 is an elevation of the end of the machine carrying the work, with portions broken away. Fig. 5 is an enlarged partial elevation of the opposite side of said end portion to that shown in Fig. l. Fig. 6 is a vertical section on the dotted line w in Fig. 1. Fig. 7 is a top detail of a portion of the parts shown in 6. Fig. 8 is a sectional detail of a portion of the means employed to impart a vertical movement to the grinding-medium taken on the-dotted line y y in Fig.

9. Fig. 9 is an end elevation of the saine with the grinding-medium removed, and Fig. 10 1s a -transverse section taken on Referring to the drawings, l1 designates the frame, which is provided at one end with the elevated portion 1a carrying the grinding parts and at the other end with the elevated portion l", carrying the work mandrel and a portion of its controlling parts. The frame portion 1a is formed on its top with a longitudinally extending slide-way 2 on which a carriage 3 is mounted for longitudinal movement relative to the frame to permit the grinding-wheel 4, which is revolubly carried at its inner end, to be moved forward and backward across the face o the gear-wheel 5,.which latter is carried as hereinafter described. The grinding-wheel 4 is journaled in a bracket 6,wh ich is slidingly carried by a head 3, formed at the inner -end of the carriage 3, for vertical adjustment relative to the lane of movement of the carriage. This adjustment is effected at each return 'movement ofthe carriage by the fractional revolution of a screw 7, which is vertically mounted in the head 3a and passes through a threaded aperture in a\boss 6a formed o n the inner side of the bracket 6, as shown in Fig. 1. A. ratchet-wheel 8 is carried at the lower end of the screw-shaft 7 and is engaged by a pawl 9, which is pivoted to a ratchet-wheel incasing member 1.0, as shown in Figs. member is loosely mounted on the screwshaft and has an arm 10a projecting therefrom in position for a screw llthereon to have contact with an alining ortion of the slide-way 2 'ust prior tothe limit of return or rearward movement` of the carriage, whereb to impart a predetermined degree of revoliition to the screw-shaft 7, the dotted lines in Fig. 8 illustrating the action of said arts. The arm 10 is normally retained atv its limit of inward movement 'relative to the carriage 3 by a coiled contraction spring 12 secured as shown in Fig. 8, and this inward movement is regulated b a contact screw 13 carried bythe arm. t is aipparent that each lowering movement of t e grindingwheel is very slight, being' only suiicient for the trimming made necessary b the wear after a grinding operation, an that such movement is regulated by the number of threads per inch on the screw 7, the number of teeth on the ratchet-wheel 8, and the throw given the pawl The grinding-wheel 4 is. driven by a belt 14, which connects the sheave 15 on the wheel shaft and the drive-sheave 16 carried by a line or other suitably driven shaft. 'The course of the, belt is guided intermediate the sheaves 15 and 16 by the two sheaves 17 17, which are carried at the rear or outer end of the carria e 3, as shown ,in Fig. 1. The requisite longitudinal movement is imparted to the carriage 3 from the rotary movement of a drum 18, which is mounted on the shaft 19 beneath the carriage, due to an idler-,roll 20, carriedat the under side of the carriage, traveling in a cam groove 21 formed in the `circumference of the drum, said groove being shaped as hereinafter more particularly described. A gear-wheel 22'is carried at the outer end ofthe shaft 19', and has connection through suitable intermediate gearing with a source of power.

Supported by the frame 1 intermediate the elevated portions 1a and 1" thereof is the frame part 23, which'in turn supports the This standard or faces formed with each end of which block' 26, which bracket has'its forward a horizontal' groove 25 in is slidingly ymounted 'a 8 and 9. This incasingincasso by a plug 32 through which an adjustingscrew 33 is threaded, said screw coacting with a spring-retainer 34, which is threaded 31. The lower end 4of each socket is closed 75 to the lower end of the post 31 and receives the thrust of the lower end of a coiled compression-spring- 35. This s ring encircles the post and has its upper end) thrust against a shoulder in the socket, as shown in Fig. 2. The post is locked in adjusted position by a bolt 36, which passes through the retainer 34 and alining vvertical slots in the socket wall, as shown. The upper end ofthe posts 31 terminate in horizontallyldisposed bearing-heads 37, which `are dispf'ised adjacent the lower arc of the grinding-wheel 4 on opposite sides thereof and in each of which is mounted a rock-shaft 38. Radially projecting from the forward ends of the shafts38` are the two opposing rear diamond-holders 39, each of which carries at one end a dia- .mondf40 for coacting with and trimming the contiguous are a. of the grinding wheel 4. Each diamond-holder 39 passes through a collar `41 carried by the shaft and is secured in adjusted position by a set-screw 42. These holders are intended to be so adjusted relative to the grinding-wheel, when at its limit of rearward movement, that the axis of each coincides with the 4axis of the conti'guous arc a of the wheel, thus causingA them, when operated, to effect a superficial trimming of the surfaces a, a, immediatel after each lowering movement of the whee. Projecting inwardly from the rear end of each shaft 38 is an. arm 43, which arms have their -inner ends lapping each other land slotted, as shown, to receive a common pin 448L carried at the upper end of the vertical push-rod 44, so that a vertical reciprocatory movement of the rod will impart a simu taneous rocking motion to the twoshafts 38 and their diamond-holders 39. This rod passes down through a hole in the standard 24 and frame part 23 and has its lower end terminating in position to coact with the conical face o-f a collar 45, which is slidingly carried by a shaft 46, whereby as said collar is moved from its normal position, by mea'is hereinafter described, the rod .is raised against the tension of the coiled compression# spring 44b to eii'ectan upward movement of the rear trimmer-diamonds 40 to trim the' Varcs a, a4 of the grinding-wheel. The conical collar 45 is returned to its normal position' by the action of the coiled compressionvlo incassa spring 47, which is mounted 'on the shaft 46 intermediate said collar and the cam-faced collar 48, which is xed to said shaft and has an additional function hereinafter described.

During the operation of the rear trimmerdiamonds 40 on the wheel 4 the idler-roll 20 of the carriage 3 is traveling in the neutral zone a of the cam groove 21 in the drum 18, and at the end ofv such Zone enters the in clined or diagonally-disposed portion b of the groove, which causes the carriage to move forward until the axis of the grindin wheel stands in vertical alinement withv t e two front trimmer-diamonds 49. At this point the idler-roll 204 enters'a second neutral zone c of the. guiding-groove and effects a momentary pause of the carriage and grinding-wheel to permit said front' trimmer-diamonds to act on the wheel before the idler-roll enters the inclined or diagonallydisposed portions al -of the guiding-groove, which moves the carriage 3 forward sulficiently for 'the wheel 4 to traverse across the face of the gear 5 for the purpose of truing the contiguous faces of two of its teeth. The guiding-groove .21 at the end of the diagonal portion al thereof is formed with a return bend and continues around the drum forming a'reverse diagonall course which meets the neutral zone a thereof, thus returning the l grinding-wheel to again be trimmed.

Mounted for reciprocal vertical movement in the socket-member 50, -secured to the top of the fr'ame part 23 in advance of the standard 24, is a plunger or push-rod 51, the lower end of which is projected through the top of said" frame part 23 in position\to coact with the cam surface of the collar 48 on the shaft 46, whereby Va raising thereof is efected when the collar is turned. The upper end of said plunger or rod is projected to `adjacent the lower edge of the grinding-wheel 4 when standing thereover and is bifurcated to form the two arms 52, 52, each of which carries one of the front trimmer-diamonds 49 at its free end in position for their pointsto abut each other when the free ends of the j arms are forced .to ether and to have con'- tact with the periphery on bead of .the grinding-wheel when the plunger is elevated. The plunger is prevented from turning in its socket by keys 53 which operate in registering grooves inthe socket walls. A. coiled compression spring 54 encircles the plunger within an enlarged part of the socket, and has its upper end abutting against a shoulder in the Socket and its lower end coacting with a collar 55 on the plunger, thus tending to normally maintain'the plunger in lowered position, as shown in Fig. 3. The lowering movement of the plunger is shown as being limited by a shoulder'la thereon coacting with a cap 50a, which is secured'to the upper end of the socket 50 and through which the plunger operates.

position so that yend of the Mounted on the socket-member 50is a collar or head 56 from the opposite sides of which project the ,twov upwardly extending arms 57, 57, the terminals of which converge and each carries an idler-roll 58 in position to engage the outer face of the contiguous arm 52 of the plunger. As the tendency of the arms 52 is to diverge or remain' in open the diamonds 49 would normally be separated, the coaction of the rolls. 58 therewith is intended to produce a conl verging of the diamonds at a predetermined point in the movement of the plunger. For this purpose the arms are provided with the raised surfaces c with which the rolls 58 coact when the plunger is down and continues to coact ,until theJ .plunger is raised sulficiently for the diamonds '49 to have contact with theI periphery or bead b of the grinding-wheel, vat which point the arms begin to spread, due to the rolls assing to the a ruptly reduced surfaces jp of the arms, thus permitting the diamonds 49 to have a diverging movement transversely of the narrow face or bead b of the rapidly revolving grinding-wheel whereby to trim the same.

The cam-collar 48, with which thelower end of the plunger or push rod 51 coacts, is provided with an abrupt projection 48a by means of which the plunger is suddenly ele- .vated when the shaft 46 is given a partial revolution. The means employed for vrocking the shaft 46, as shown in Figs. 1, 6 and. 7, consists of a pin 59, which projects from said shaft in position to be struck by a finger 6.0 at each revolution of the drum '18, said finger being adjustably secured to the inner drum; The shaft 46 and collar 48 are automatically returned to their normal position after the finger 60 has released the pin 59, due to the action of the coiled contraction-spring 61, which has one end fixed to a pin projecting from said'collar and its other end ixed to a convenient portion of the frame, as shown in Fig. 3. rl`he return or backward movement of the shaft is l1mitedby a lug 62 on the collar 48 engaging a stop 68 secured to a contiguous frame portion.

rlhe gear-wheel 5 to be trued is carried v`at the inner end of the horizontal `arborshaft or mandrel 64, which is journaled in the elevated portion 1b of the frame and carries the index-wheel or disk `65 at its outer end. The mechanism shown in Figs. 1, 4, 5, 6 and 7 by means of which the index wheel is moved with mechanical precisionthrough any required portion of a lio revolution and locked in any adjusted posil tion consists in loosely mounting a ratchet wheel 66 on the mandrel 64 within a housing or casing 67 on the inner face of the index-wheel 65. This ratchet-wheel has an arm 68 'radially projecting therefrom through a suitable opening in the casing 67 and when .moved by a raisingr'of said arm upper end engages one of the peripheral 'has its teeth engaged by a spring-pressed pawl .69 which is carried by the housing 66 of the index-wheel so that movement is communicated thereby to the latter. An adjustablerod 70 connects the arm 68 with an arm 71 -projecting from the disk-like member 72, which is loosely mounted ony the rock-shaft 73 without the' frame 1. The arm 71 has its lowering' movement limited by a radial lug .74 on the member 72 coacting with a stop-screw 75 carried by the adjoining frame part. The shaft 73 is transversely journaled in the frame 1 beneath the arborshaft 64 and has a disk 76 fixed to its inner end within the frame 1, as shown in Fig. 1, and an arm 77 liXed to its outer end in position to coact with a screw 78 carried by a lug 79 on the face of the member 72. When the shaft 73 isV rocked, as hereinafter dei scribed, the arm 77, after firstA having a limited movement relative to the member 72, engages the screw 78 thereon'to impart the requisite turning movement to said member for the purpose of elevatin the rod 70 to effect a movement of the in eX-wheel 65.

A rod orfiink 80 connects the disk 76 with the lower end of a lever v,81, which is fulcrumed to an arm projecting from the frame 1 beneath the shaft 46 and has its upper end forked and positloned to engage the lugs 82,

vwhich project in opposite directions from the sleeve 83. This sleeve is slidingly car-- ried by the 'shaft 46 beneath the drum 18, and carries an idler-roll 84 for traveling in the cam-groove 21 of the drum, whereby a rotation ofthe drum imparts a recprocatory movement to the sleeve. ted, as at 83a to permit its forward end to move past the pin 59 on its shaft. At a predetermined point in the forward movement of the sleeve the lugs .82 thereon engage the forked end of the lever 81, causing an oscillation thereof and a consequent partial rotation of the disk 76 and shaft 73. In order to prevent a turning of the sleeve 83 an' arm 83b projects from one side thereof and has its outer end forked to have a sliding movement on a fixed bar 83, which is mounted in parallelism with the sha-ft 46, as shown in Figs. 6 and 7. A's the disk =76 is rotated an idler-roll 85 thereon moves upon a camsurface 86 formed on the upper side of the arml 87, and causes a depression of the. arm, which depression is malntained during the remainder of the stroke.- 4The arm .87 is nivoted at its rear end to a boss 88, projecting inwardly from one side of the frame 1,

and has its forward end forked and embracing the grooved collar 89, which is carried at the lower end ofthe vertical rod 90. This rod is mounted for vertical movement within a holder 91A secured to the end of the' frame 1 and is normally retained elevated by the action Aof the spring 90 so that its The sleeve is slot? .51.

, notches 65a in the index-wheel 65 whereby to vserve as a stop therefor.

The journal-box in which the arbor-shaft or mandrel 64 is mounted is vertically adjusted by a handscrew 92 toaccommodate. the machine to the truing of different sized gears; To permit of this adjustment the vertical rods and.

90. of the index-wheel controlling mechanism are both made longitudinally adjustable, as shown.

Thesliding-sleeve 83 on the shaft 46, in addition to communicating motion from the drum 18 to the lever 81 of the work-control ling mechanism, also serves as a means for actuating the movement of the conical collar 45 carried on the shaft 46 therewith, as it engages the end of said collar justprior to its (the sleeves) limit of forward movement, or approximately at the time the idler-roll` 20 of the carriage 3 enters .the neutral zone a of the cam-groove 21 thus effecting a forward movementof the collar ,45 against the tension of the' spring 47 and a properly timed raising ofthe push-rod 44 to operate the rear trimmer-'diamonds 40.

In Figs. 1, 2 and 3 is illustrated a suitable mechanism for manually controlling the trimming movements of the two sets of diamonds. This mechanism comprises a shaft 93, which is journaled in thel frame part 23 in parallelism with the shaft 46, as `shown in said figures, and carries an arm 94 for engaging the under side of a pin 95 projecting from the push-rod 44, and an arm 96 for having like engagement with-a pin 97 projecting from the plunger or push-rod The shaft 93 is mounted to have a limited longitudinal movement inl its bearings and the arms 94 and 95 are relatively positioned thereon so that when the shaft is at the limit of inward movement the former only is in position to engage its pin, and when at its limit of outward movement the latter only is in position to' engage its pin.

An operating handle 98 is carried at the j the plunger or push-rod 51 will be effected.

The operation of the machine is as follows: The work being positioned on the arbor-shaft or mandrel 64, which is properly adjusted to suit the size of the same, the means drivingthe gear-wheel 22 -is thrown into operation to impart the proper rotation to the drum 18, which in turn communicates a properly timed longitudinal reciprocatory movement to the 'carriage 3 due to the idler-roll 20 carried thereby travelin in the 'circumferential cam-'groove 21 of t e drum. The forward movement of the carriage causes -the rapidly revolving grinding-wheel 4, carried thereby, to traverse the upper face of the work between two ofthe teeth thereof, thus t-ruing or removy When the grinding-wheel has traversed the face of the work the movement of the carriage is -reversed and the wheel therebv returned through the same groovev or space ofthe work to its original point of starting. As the carriage nears its limit of rearward movement the screw 11 carried by the armV 10a has contact with an alining stationary portion of the frame 1, thus 'effecting an oscillation of said arm and causing the dog or pawl 9 carried ythereby to engage and impart a fraction of a revolution to the ratchet-wheel 8 and screw 7 to which said wheel is fixed and effecting a very slightlowering of the grinding-wheel. The lowering.mechanism 1s so regulated and adiusted that the movement imparted to the grinding- `'whe'el islonly suilicient to allow for the necessary trimming of the wheel in order to true it after a. grinding operation. The grinding-wheel having been lowered. the idler-roll 20 enters the neutral zone a of the cam-groove 21, thus ycausing a slight pause of the carriage 3 before again starting'on its forward movement. During such pause the sliding-sleeve 33 on the shaft 46 strikes the extended end of the conical collar 45. moving it Vforward against the tension of the compression-spring 47 and efecting an elevation of the push-rod 44 due to the. coaction of its lower end with the conical surface of the collar. This raising of the rod imparts simultaneous rocking movements to thel two rear-trimmer diamond-holders `39, through the medium of the shafts 38 and arms 43, and causes the rear trimmer-diamonds 40 to move upward in unison in arcs concentric to the arcs w, a of the grindingwheel whereby to trim suchsurfaces preparatory to said wheel truing the succeeding groove or space in the gear-wheel being operated on to that trued in the previous operation. After the push-rod 44 has been elevated the idler-roll 20- enters the diagonally-disposed portion b of the guidinggroove 21 which causes the carriage to -move forward a sufficient dist-ance for the axis of the grindin wheel to stand in vertical alinement with the front trimmer-diamonds '49 of the trimming mechanism. .At this point the idler-roll 20 enters the second neutral zone o of t-he groove 21, causing the carriage to again pause in its movement, during which pause the finger 60, carried by `the drum' 18,`coacts with the pin 59 carried by the shaft 46. As the'iinger strikes the!) l pin the shaft 46 and collar 48 thereon-arge? rocked suiiciently to throw the cam projection 48a on said 'collar under the lower end of the plunger or' push-rod 51, whereby to raise sa1d plunger in position for the trimmer-diamonds 49 carried at its upper end to coact with the periphery or bead b of the grinding-wheel At approximately the point of contact of the diamonds 49 with the grinding-wheel the idler-rolls 58 Vpass abruptly from the raised surfaces e tothe reduced surfaces f of the arms 52 of the plunger, thus permitting the diamonds 49 to have a diverging movement transversely of the narrow face or bead b of the rapidly revolving grindingwheel, whereby to effect a smooth and even trimming of such surface. Upon a release of the two push-rods 44 and 51 they are, respectively, actuated by the springs 44b and 54 to return'to their normal lowered positions. A manual raising of the. rods 44 and 51 may be effected by moving the shaft 93 in or out, respectively, and pressing down on the handle 98y so that the arms 94 will coact with the pin 95 on the rod 44 or the arm 96 will coact with the pin 97,v as the case may be, and effect a raising of the respective rods. Near 'the limit of rearward movement of the carriage 3 the disk 76 receives a partial revolution, due to the sliding-sleeve 83 on the shaft 46 striking and` oscillating the lever 81. As the disk is turned the idler-roll 85 carried thereby moves upon the raised cam-surface 86 of the pivoted arm 87, eecting a depression .thereof and a consequent disengagement of the member 90 from the registering notch in the index-wheel 65. The arm 71, which is keyed' to the shaft with the disk 76 and turns therewith, is adjusted relative to the screw 75 carried by the member 72 so that it engages said screw immediately upon the release of the locking-member 90 from engagement with the index-wheel and eifects a raising of the rod 70 and a consequent partial rotation of the ratchet-wheel 66. As the ratchet-wheel is moved it engages the pawl 69 and imparts the requisite movement to the index-wheel and arbor-shaft or mandrel 64 to rotate the gear-wheel 5 the distance of one tooth, so that each groove of the` gear-wheel is successively acted on by the grinding-wheel. Upon a release of the rod 90 it is elevated by the action of the spring 90a. i

`While we l anism as associated with a particular style of gear-truing machine, we wish it understood that we do not li-mit ourselves to its use in such connection, nor do we wish to restrict our invention to the particular construction or arrangement of the parts shown and described, as obvious modifications will Pl., occur to one skilled in the art.

have shown our trimming mechv lill@ what we claim as new and desire to secure by Letters Patent, is

1. In a machine for grinding gears or doing similar work, the combination of a grinding medium, for imparting a given contourv to the work, means for supporting the gear to be operated upon, mechanism for imparting relative movement to thev grind-` ing medium and .gear support to cause the grinding medium to engage the work, and

of the teeth by and in accordance with the working face of said medium, and means coperating with the grinding medium to trim the'I operating surfaces thereof and maintain at said surfaces the contour to be applied to the gear. .i

3. In a machine for grinding gears or doin similar work, the combination of a grin ing medium, supporting and indexing mechanism yfor the gear to be operated upon,

mechanism for imparting relative movement to the grinding medium and gear support, and means coperating with the grinding .medium to trim the operating surface thereof to thecon'tour to be imparted to the gear. 4. In-` a, machine for grinding gears or doin similar work, the combination of a grin ing wheel having its eripheral portion shaped to conform to tkib surface to be ound, supporting and indexing mechanism or the gear, means for imparting relative movement tothe grinding wheel and thev 45 gear support to cause the wheel to engage successive teeth of the ear, and mechanism coperating with the grinding wheel to trim the peripheral ortion thereof and maintain the same o the exact contour to be imparted to the gear.

l 5. In a machine for grinding gears or doing similarwork, the combination of a rotatable grinding medium, the operating surface of which conforms to the working face ear teeth into vcoperative engagement to e ect a grinding of the gear tooth, means for supporting the gear, mechanism for imparting relative movement to the grinding medium and gear vsupport and for intermittently indexing the ing the gear tobe operated upon, mechanism 4 for bringing the working face 'of the grinding medium and the gear teeth into operative engagement, and a` trimming mechanism coperating with the grinding medium to restore the working face to its normal contour when said face becomes deformed.

7. The method of grinding gears or like articles to an exactly predetermined form, comprising the mounting of a rotary grinder in an organized work grinding machine, the trimming of the grinder wheel while thus mounted to fashion or re-fashion the cross sectional contour thereof to a predetermined form exactly complemental to the contour of each of a series of like segments in the cross section o f the finished work, and in grinding the work by successively presenting segments thereof to the operation of the grinder.

8. The combination with an organized machine for grinding gears and the like, including a rotary work holder, an indexing mechanism therefor and a its axis transverse to the axis of the work, of means forming a part of the organized unit^for trimming the grinder wheel to a predetermined cross sectional contoui` ex. actly complementary to each of. a series of like segments in the contour of the finished work.

In testimony whereof we aiiix' our signa-` tures in presence of two witnesses.

I FREDERICK'ALEXANDER WARD.

WILLIAM NEWTON TAYLOR. Witnesses as to F. A. Ward:

GEO. P. Conn, Y N. C. BANKS. Witnesses as to W. N. Taylor:

, GEO. P. Conn,

--BERTHA L. TAYLOR.

rinder havingV 

